Golf ball having layers with specified moduli

ABSTRACT

A golf ball or other layered article may include three thermoplastic layers and one thermoset layer. The flexural moduli of the thermoplastic materials may be selected to have specified ratios. The ratio of the first flexural modulus to the third flexural modulus may be between about 6 and about 30. The ratio of the second flexural modulus to the first flexural modulus may be between about 2 and about 8. The ratio of the second flexural modulus to the third flexural modulus may be between about 50 and about 180.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation-in-part of co-pending application Ser. No. 12/860,785, entitled “Golf Ball Having Layers With Specified Moduli and Hardnesses” filed Aug. 20, 2010, the disclosure of which is hereby incorporated by reference.

This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 61/512,675, entitled “Golf Ball Having Layers With Specified Moduli”, and filed on Jul. 28, 2011, which application is hereby incorporated by reference.

BACKGROUND

The present invention relates generally to a golf ball having layers with specified moduli in specific relationship to one another.

A golfer typically selects a golf ball that has a combination of features based on his or her preferences and/or skill level. A golf ball designer often attempts to balance the preferences of a variety of golfers to provide high satisfaction from many golfers using the same golf ball. Frequently, a designer designs a golf ball having a plurality of layers, with each layer helping to provide a desirable quality.

For example, a golfer may select a golf ball having a particular compression, selected based on a golfer's skill and performance. For example, when a golfer has a low club head speed, softer compression is often desirable. Matching a golfer's compression and club head speed can often optimize the golfer's driving distance.

In other examples, the material from which the layers are made can be important. Different materials have different hardness and resiliency values. These differences affect the way the golf ball carries, rolls, spins, sounds, and feels to the golfer when the ball is hit.

However, a designer may also consider the combined effect of the layers when selecting materials for a golf ball. The layers of a golf ball may all deform when a golf ball is hit, and the properties of all the layers thus combine to affect the flight path and distance of a golf ball. Even when fewer than all layers deform, the interplay of the layers of a solid golf ball impacts ball performance and the golfer's perceptions of that performance.

Many of the materials used in golf balls include thermoplastic materials. When a thermoplastic material is considered, it is often desirable to select such a material based on its flexural modulus or, generally, its tendency to bend when under load.

In addition, materials commonly used in golf balls may vary in hardness. Some golf balls may include a softer material as the outermost layer to improve the feel of the ball to a golfer, for example.

Accordingly, it is desirable in some cases to design a golf ball based on the desired flexural modulus, the desired hardness, or both, of each layer of the ball. The combined golf ball may then be used by many golfers to provide a good balance between the layers to provide an appropriate feel, spin control, and distance.

SUMMARY

For many golfers, the feel of a golf ball is important to enjoyment of a game of golf, in addition, of course, to accuracy and a low score. A golfer, when striking the ball, may observe the ball's “feel” without fully appreciating the design aspects of the ball that contribute to the feel of the ball when struck. In many circumstances, a golf ball or other layered article designer may select a variety of materials for use to create a desired feel. In some embodiments, the designer may select materials for different layers of the ball or layered article that differ in flexural modulus. In other embodiments, the designer may select materials that differ in hardness. In other embodiments, the designer may select materials that differ in density or specific gravity. By selecting materials that have a certain ratio of measured values, the designer may develop a ball or layered article that has desired performance characteristics and a desired feel.

In one aspect, a golf ball may include a first core layer, a first cover layer, and a second cover layer. The first cover layer may be radially outward of the first core layer. The second cover layer may be radially outward of the first cover layer. The first core layer may have a first flexural modulus. The first cover layer may have a second flexural modulus. The second cover layer may have a third flexural modulus. The second flexural modulus may be at least twice the first flexural modulus. The second flexural modulus may be at least fifty times the third flexural modulus. The first flexural modulus may be at least six times the third flexural modulus.

In another aspect, a layered article may include a first layer, a second layer, and a third layer. The first layer may have a first flexural modulus. The second layer may have a second flexural modulus. The third layer may have a third flexural modulus. The first layer, the second layer, and the third layer may be positioned adjacent one another. The first flexural modulus may be between six times and thirty times the third flexural modulus. The second flexural modulus may be between fifty times and one hundred eighty times the third flexural modulus. The second flexural modulus may be between two and eight times the first flexural modulus.

The multi-layered golf ball or layered article may have layers that each have specific material and mechanical properties relative to the other layers. When the ball is so designed, the ball may respond and feel differently when encountered differently. For example, the ball may feel and respond in one manner when struck with a driver or wood and may feel and respond in another manner when struck with an iron or wedge. In some embodiments, it may be desirable when the ball is struck with a wood or driver that the ball has an optimized distance and accuracy. In some embodiments, it may be desirable when the ball is struck with an iron or wedge that the ball has an optimized feel and spinnability. In some embodiments, the golf ball may be provided with various thermoplastic and thermoset layers. The flexural modulus of each thermoplastic layer may be selected so that the material having the highest flexural modulus is positioned near a ball's outer surface. In many embodiments, the outermost layer may have the lowest flexural modulus. In many embodiments, the coefficient of restitution (COR) of the materials may be selected so that the COR of the layer or layers forming the core may be higher than the COR of the ball as a whole.

In many embodiments, the use of a relatively low flexural modulus material for the outermost cover layer may increase the good feel of the golf ball when a golfer strikes the ball to make a short iron shot or a putt. The use of such a low flexural modulus material may also increase backspin on such shots in some embodiments. In many embodiments, the use of a relatively high flexural modulus material for a layer near the outermost cover layer may reduce the backspin of the golf ball and increase the flight distance of the ball when a golfer strikes the ball with a driver, a fairway wood, or a long iron, particularly off a tee. In many embodiments, the use of a relatively intermediate modulus material as an inner layer, or in some embodiments of an innermost layer, of a golf ball may further reduce the ball's backspin when a golfer strikes the ball with a driver.

Other systems, methods, features and advantages of the invention will be, or will become, apparent to one of ordinary skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description and this summary, be within the scope of the invention, and be protected by the following claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like reference numerals designate corresponding parts throughout the different views.

FIG. 1 is a side view of a golf ball according to the present disclosure; and

FIG. 2 is a cross sectional view of the golf ball of FIG. 1 taken along line 2-2.

DETAILED DESCRIPTION

A golf ball or other layered article may include three thermoplastic layers and one thermoset layer. The flexural moduli of the thermoplastic materials may be selected to have specified ratios. The ratio of the first flexural modulus to the third flexural modulus may be between about 6 and about 30. The ratio of the second flexural modulus to the first flexural modulus may be between about 2 and about 8. The ratio of the second flexural modulus to the third flexural modulus may be between about 50 and about 180.

The golf ball may be made by any suitable process. The process of making the golf ball may be selected based on a variety of factors, but in most embodiments will generally include injection molding the resin inner core, compression molding the rubber outer core onto the resin inner core, and then injection molding the resin cover onto the rubber outer core. For example, the process of making the golf ball may be selected based on the type of materials used and/or the number of layers included. Exemplary processes are discussed below with respect to the individual layers of the exemplary embodiment.

As used herein, the term “about” is intended to allow for engineering and manufacturing tolerances, which may vary depending upon the type of material and manufacturing process, but which are generally understood by those in the art. Also, as used herein, unless otherwise stated, compression, hardness, COR, and flexural modulus are measured as follows:

Compression deformation: The compression deformation herein indicates the deformation amount of the ball under a force; specifically, when the force is increased to become 130 kg from 10 kg, the deformation amount of the ball under the force of 130 kg subtracts the deformation amount of the ball under the force of 10 kg to become the compression deformation value of the ball. All of the tests herein are performed using a compression testing machine available from Automated Design Corp. in Illinois, USA or EKTRON TEK Co., LTD.; Model name: EKTRON-2000 GBMD-CS. Both compression tester machines can be set to apply a first load and obtain a first deformation amount, and then, after a selected period, apply a second, typically higher load and determine a second deformation amount. Thus, the first load herein is 10 kg, the second load herein is 130 kg, and the compression deformation is the difference between the second deformation and the first deformation. Herein, this distance is reported in millimeters. The compression can be reported as a distance, or as an equivalent to other deformation measurement techniques, such as Atti compression.

Hardness: Hardness of golf ball layer is measured generally in accordance with ASTM D-2240, but measured on the land area of a curved surface of a molded ball. Other types of hardness, such as Shore C or JIS-C hardnesses may be provided as specified herein. For material hardness, it is measured in accordance with ASTM D-2240 (on a plaque).

Method of measuring COR: A golf ball for test is fired by an air cannon at an initial velocity of 131 ft/s, and a speed monitoring device is located over a distance of 0.6 to 0.9 meters from the cannon. When striking a steel plate positioned about 1.2 meters away from the air cannon, the golf ball rebounds through the speed-monitoring device. The return velocity divided by the initial velocity is the COR. A COR measuring system is available from ADC.

Durability: Durability is generally measured by following the protocol for measuring COR, as described above, for 150 shots or until the golf ball fails. When the golf ball fails, the COR noticeably and suddenly drops.

Flexural Modulus: The material is measured generally in accordance with ASTM D790, which measures the deflection in a beam of the material in a three point bending system.

Any ball described herein is considered conforming if the ball adheres to the Rules of Golf established by the United States Golf Association (USGA). All other balls are considered non-conforming.

FIG. 1 is a side view of a golf ball 100 that may be used in accordance with the technology disclosed herein. Although the disclosure describes various embodiments relating to golf balls, a person having ordinary skill in the art is able to adapt the disclosure for use in connection with other types of balls for other uses and for use in other types of desired layered articles. The technology described herein may be applicable to any layered article, such as, for example, a projectile, ball, recreational device, or component thereof.

FIGS. 1 and 2 show a generic dimple pattern applied to outer surface 102 of golf ball 100. While the dimple pattern on golf ball 100 may affect the flight path of golf ball 100, no specific dimple pattern is critical to the use of the disclosed embodiments. In the present disclosure, a designer may select from any appropriate dimple pattern to be applied to the outer surface of golf ball 100. In some embodiments, a designer may select a dimple pattern having a total number of dimples between 300 and 400.

FIG. 2 is a cross-sectional view of golf ball 100 taken along line 2-2 of FIG. 1. As shown in FIG. 2, golf ball 100 may have four layers that are positioned adjacent one another. First layer 204 may be a first or inner core layer. Second layer 208 may be a mantle or inner cover layer and is positioned radially outwardly of first layer 204. Third layer 210 may be an outer cover layer and is positioned radially outwardly of second layer 208. Fourth layer 206 may be an outer core layer and may be positioned radially outwardly of first layer 204 and may be positioned between first layer 204 and second layer 208. First or inner core layer 204 and fourth or outer core layer 206 may together be considered and referred to core 212. Second layer 208 and third layer 210 may together be considered and referred to as cover 214. Any layer may surround or substantially surround any layers disposed radially inward of that layer. For example, fourth layer 206 may surround or substantially surround first layer 204.

In the present disclosure and drawings, golf ball 100 has been described and illustrated as having four layers. In some embodiments, at least one additional layer may be added. For example, in some embodiments, a mantle layer may be added between core 212 and cover 214. In other embodiments, an intermediate cover layer may be inserted between second layer 208 and third layer 210. In other embodiments, an intermediate core layer may be inserted between first layer 204 and fourth layer 206. Other layers may be added on either side of any disclosed layer as desired by a designer.

The layers of golf ball 100 may be made of any material known in the art. Suitable known materials for use in a golf ball include thermoset materials, such as rubber, styrene butadiene, polybutadiene, isoprene, polyisoprene, certain types of polyurethanes, and trans-isoprene. Known materials also include thermoplastics, such as ionomer resins, polyamides or polyesters, and thermoplastic polyurethane elastomers. Suitable materials also include polyurea compositions, as well as other materials.

In some embodiments, first layer 204 may be made of a first thermoplastic material. Second layer 208 may be made of a second thermoplastic material. Third layer 210 may be made of a third thermoplastic material. Each of first thermoplastic material, second thermoplastic material, and third thermoplastic material may be selected from among various conventional thermoplastic materials. More specifically, each of first thermoplastic material, second thermoplastic material, and third thermoplastic material may be selected from among the following materials: an ionomer resin, a highly neutralized acid polymer composition, a polyamide resin, a polyester resin, a polyurethane resin, and a combination of two or more of these materials. Examples of ionomer resins that may be desirable for use with the present embodiments include SURLYN®, commercially available from E.I. DuPont de Nemours and Company, and IOTEK®, commercially available from Exxon Corporation. Examples of highly neutralized acid polymer compositions may include HPF resins, such as HPF1000, HPF2000, HPF AD1027, HPF AD1035, HPF AD1040, commercially available from E.I. DuPont de Nemours and Company. Each of first thermoplastic material, second thermoplastic material, and third thermoplastic material may be selected from the same or different types of thermoplastic materials. In some embodiments, second thermoplastic material may include a non-ionomeric material and third thermoplastic material may include a non-ionomeric material. In some embodiments, for example, first thermoplastic material may include a highly neutralized polymer composition, second thermoplastic material may include a polyurethane resin, and third thermoplastic material may include a polyurethane resin. If second thermoplastic material and third material include the same type of thermoplastic material, good adhesion between second layer 208 and third layer 210 may be promoted.

Fourth layer 206 may be made primarily or entirely of a thermoset material. The thermoset material may include a rubber compound. If the thermoset material is a rubber compound, a base rubber may be used. In some embodiments, cis-1,4-polybutadiene may be used as the base rubber and mixed with other ingredients. In some embodiments, the amount of cis-1,4-polybutadiene may be at least 50 parts by weight, based on 100 parts by weight of the rubber compound. Various additives may be added to the base rubber to form a compound. The additives may include a cross-linking agent and a filler. In some embodiments, the cross-linking agent may be zinc diacrylate, magnesium acrylate, zinc methacrylate, or magnesium methacrylate. In some embodiments, zinc diacrylate may provide advantageous resilience properties. The filler may be used to increase the specific gravity of the material. The filler may include zinc oxide, barium sulfate, calcium carbonate, or magnesium carbonate. In some embodiments, zinc oxide may be selected for its advantageous properties. Metal powder, such as tungsten, may alternatively be used as a filler to achieve a desired specific gravity. A person having ordinary skill in the art will be able to determine an appropriate specific gravity for the thermoset material for use in fourth layer 206 of golf ball 100. In some embodiments, the specific gravity of the thermoset material may be between about 1.05 g/mm² and about 1.25 g/mm². In some embodiments, the specific gravity may be about 1.12 g/mm². Finally, fourth layer 206 may have a surface Shore D hardness of from 50 to 60.

In some embodiments, a polybutadiene synthesized using a rare earth element catalyst may be used. The use of such a synthesized polybutadiene may improve the resilience of golf ball 100 as a whole. Examples of rare earth element catalysts include lanthanum series rare earth element compound, organoaluminum compound, and almoxane and halogen containing compound. A lanthanum series rare earth element compound may be used in some embodiments. Polybutadiene obtained by using lanthanum rare earth-based catalysts usually employ a combination of a lanthanum rare earth (atomic number of 57 to 71) compound. A neodymium compound may be used as the catalyst in some embodiments.

The materials used to make the layers of golf ball 100 may interrelate with each other to provide playing characteristics to the golf ball as a whole. The materials used to make golf ball 100 may differ in flexural modulus and hardness. Selecting materials within a specified range and with a specific relationship between the materials and layers may provide desirable results for a golfer. For many golfers, it may be desirable that a golf ball has a good feel and spin control for short shots, while maintaining distance upon tee shots and long iron shots. The materials and properties may be selected to optimize these results.

In many embodiments, the use of a relatively low flexural modulus material for the outermost cover layer may increase the good feel of the golf ball when a golfer strikes the ball to make a short iron shot or a putt. The use of such a low flexural modulus material may also increase backspin on such shots in some embodiments. In many embodiments, the use of a relatively high flexural modulus material for a layer near the outermost cover layer may reduce the backspin of the golf ball and increase the flight distance of the ball when a golfer strikes the ball with a driver, a fairway wood, or a long iron, particularly off a tee. In many embodiments, the use of a relatively intermediate modulus material as an inner layer, or in some embodiments of an innermost layer, of a golf ball may further reduce the ball's backspin when a golfer strikes the ball with a driver.

The thermoplastic materials used to make first layer 204, second layer 208, and third layer 210 have a specified relationship in terms of their respective flexural moduli. The flexural modulus of each thermoplastic material may be determined using the testing method described in ASTM D790. First thermoplastic material, used to form first layer 204, may have a first flexural modulus. In some embodiments, the first flexural modulus may be between about 6,000 PSI and about 40,000 PSI. In other embodiments, the first flexural modulus may be between 7,000 PSI and 40,000 PSI. In other embodiments, the first flexural modulus may be between 6,000 PSI and 35,000 PSI. In other embodiments, the first flexural modulus may be between 7,000 PSI and 35,000 PSI.

Second thermoplastic material, used to form second layer 208, may have a second flexural modulus. In some embodiments, the second flexural modulus may be between about 50,000 PSI and about 100,000 PSI. In other embodiments, the second flexural modulus may be between 50,000 PSI and 90,000 PSI.

Third thermoplastic material, used to form third layer 210, may have a third flexural modulus. In some embodiments, the third flexural modulus may be between about 200 PSI and about 3,000 PSI. In other embodiments, the third flexural modulus may be between 300 PSI and 3,000 PSI. In other embodiments, the third flexural modulus may be between 200 PSI and 2,000 PSI. In other embodiments, the third flexural modulus may be between about 300 PSI and about 2,000 PSI. In other embodiments, the third flexural modulus may be between 200 PSI and 1,000 PSI. In other embodiments, the third flexural modulus may be between about 300 PSI and about 1,000 PSI. In other embodiments, the third flexural modulus may be between about 200 PSI and about 900 PSI. In other embodiments, the third flexural modulus may be between about 300 PSI and about 900 PSI.

It may desirable in some embodiments for the flexural moduli of the materials to have a specified relationship. In some embodiments, it may be desirable for the second flexural modulus of the second thermoplastic material to be greater than the first flexural modulus of the first thermoplastic material. In some embodiments, it may also be desirable for the first flexural modulus of the first thermoplastic material to be greater than the third flexural modulus of the third thermoplastic material. In some embodiments, it may also be desirable for the second flexural modulus of the second thermoplastic material to be greater than the third flexural modulus of the third thermoplastic material.

In some embodiments, it may be desirable to select the materials forming the ball in a manner to have a certain ratio of flexural modulus values or for the value of the flexural modulus of one material to be a certain amount higher than the value of the flexural modulus of another material. In discussing such ratios, it may be understood by a person having ordinary skill in the art that such values may differ if measured with a measurement other than PSI. A person having ordinary skill in the art is able to make the appropriate conversions to a different measurement system and the values discussed herein are expressly understood as encompassing the converted values as well.

In some embodiments, the second flexural modulus may be or may have a value that is at least about twice or about 2 times that of the first flexural modulus. In such embodiments, the ratio of the second flexural modulus to the first flexural modulus may be about 2 or greater. In some embodiments, the second flexural modulus may be or may have a value that is less than about 8 times that of the first flexural modulus. In such embodiments, the ratio of the second flexural modulus to the first flexural modulus may be about 8 or less. In some embodiments, the second flexural modulus may be or may have a value between about 2 and about 8 times the first flexural modulus. In such embodiments, the ratio of the second flexural modulus to the first flexural modulus may be between about 2 and about 8.

In some embodiments, the first flexural modulus may be or may have a value at least about 6 times that of the third flexural modulus. In such embodiments, the ratio of the first flexural modulus to the third flexural modulus may be about 6 or greater. In some embodiments, the first flexural modulus may be or may have a value less than about 30 times that of the third flexural modulus. In such embodiments, the ratio of the first flexural modulus to the third flexural modulus may be about 30 or less. In some embodiments, the first flexural modulus may be or may have a value between 6 and 30 times the third flexural modulus. In such embodiments, the ratio of the first flexural modulus to the third flexural modulus may be between about 6 and about 30.

In some embodiments, the second flexural modulus may be or may have a value at least about 50 times that of the third flexural modulus. In such embodiments, the ratio of the second flexural modulus to the third flexural modulus may be about 50 or greater. In some embodiments, the second flexural modulus may be or may have a value less than about 180 times that of the third flexural modulus. In such embodiments, the ratio of the second flexural modulus to the third flexural modulus may be about 180 or less. In some embodiments, the second flexural modulus may be or may have a value between 50 and 180 times the third flexural modulus. In such embodiments, the ratio of the second flexural modulus to the third flexural modulus may be between about 50 and about 180.

The various golf ball layers also have specific hardness ranges. The hardness of each material may be measured on its curved surface (on the ball as opposed to on a plaque) using a standard testing protocol such as ASTM D2240. When hardness is referred to in this disclosure, such a testing protocol is understood to be used for that measurement. First layer 204 has a first hardness. Second layer 208 has a second hardness. Third layer 210 has a third hardness. Fourth layer 206 has a fourth hardness. In some embodiments, the second hardness may be greater than the first hardness, the second hardness may be greater than the third hardness, and the second hardness may be greater than the fourth hardness. In some embodiments, the second hardness is at least 10 Shore D units harder than the third hardness. In some embodiments, the second hardness is at least 60 Shore D or at least 65 Shore D. In some embodiments, the third hardness is from 45 to 60 Shore D. The use of a golf ball with second layer 208 as the hardest layer, particularly in embodiments where the hardness of second layer 208 is at least 10 Shore D units higher than the hardness of third layer 210, may allow for greater spin control, while maintaining a soft feel of the golf ball.

Various layers of the golf ball may be characterized in terms of their respective coefficients of restitution (COR). In order to measure the COR of an object, the object is fired by an air cannon at an initial velocity of about 40 meters per second. The object can be a portion of a finished golf ball or the complete golf ball. A steel plate is positioned about 1.2 meters from the cannon, and a speed monitoring device is located at a distance of about 0.6 to about 0.9 meters from the cannon. The object is fired from the air cannon, and passes the speed monitoring device to determine an initial velocity. The object then strikes the steel plate and rebounds back past the speed monitoring device to determine the return velocity. The COR is the ratio of the return velocity over the initial velocity. The COR measurement is dependent upon the initial velocity of the ball. As discussed herein, the initial velocity is about 41 m/s.

In some embodiments, it may be desirable for first layer 204 to have a first COR between about 0.79 and 0.92. In some embodiments, it may be desirable for first COR to be about 0.808. Core 212 has a second COR. Golf ball 100 has a third COR. In some embodiments, it may be desirable for first COR to be higher than second COR. In some embodiments, it may be desirable for first COR to be higher than third COR. In some embodiments, it may be desirable for third COR to be about 0.77. In some embodiments, it may be desirable for first COR to be about 0.038 higher than third COR. By using such COR properties, it may be possible to optimize flight distance and feel of the golf ball.

Other properties may be desirable for golf ball 100. In some embodiments, it may be desirable for golf ball 100 to have a moment of inertia between about 82 g/cm³ and about 90 g/cm³. Such a moment of inertia may produce a desirable distance and trajectory, particularly when golf ball 100 is struck with a driver or flying against the wind.

In some embodiments, first layer 204 may have a first specific gravity, second layer 208 may have a second specific gravity, third layer 210 may have a third specific gravity, and fourth layer 206 may have a fourth specific gravity. In some embodiments, fourth layer 206 may have a fourth specific gravity greater than the first specific gravity by at least 0.01. In some embodiments, second layer 208 may have a second specific gravity greater than the fourth specific gravity by at least 0.01.

The compression deformation of first layer 204 may also be designed to fall in a desirable range. The compression deformation or deflection of core 212 may be measured in a standard test method. Specifically, core 212 may be subjected to an initial force of 10 kg to a final force of 130 kg. The difference between the deformation amount from the 130 kg force and the 10 kg force is considered the compression deformation. In some embodiments, it may be desirable for core 212 to have a compression deformation between about 2.2 mm and about 4 mm. When compression deformation is referred to in the present disclosure, it is understood that such a testing protocol is used to determine that compression deformation.

In one exemplary embodiment, first layer 204 may have a first thickness or first diameter between about 19 mm and about 32 mm, and may in some embodiments have a diameter of about 24.5 mm. First layer 204 may have a first weight of about 8.30 g. First layer 204 may have a first compression deformation of about 3.68 mm. First layer 204 may have a first hardness of about 49 Shore D. Second layer 208 may have a second thickness between about 0.6 mm and about 1.2 mm and may in some embodiments have a second thickness of about 0.94 mm. Second layer 208 may have a second weight of about 5.2 g. Second layer 208 may have a second hardness of about 68 Shore D. Combined core 212 and second layer 208 may have a second compression deformation of about 2.75 mm. Third layer 210 may have a third thickness of about 1.1 mm, and in some embodiments may have a third thickness greater than the second thickness of second layer 208. Third layer 210 may have a third weight of about 6.5 g. Third layer 210 may have a third hardness of about 51 Shore D. The combined thickness of second thickness and third thickness may be at least about 1.93 mm. Fourth layer 206 may have a fourth thickness between about 5 mm and about 9 mm, and may in some embodiments have a fourth thickness of about 7.05 mm. Fourth layer 206 may have a fourth weight of about 25.4 g. Fourth layer 206 may have a fourth hardness of about 58 Shore D. Core 212 may have a core compression deformation between about 2.2 and about 4 mm, and in some embodiments may have a core compression deformation of about 3.05 mm. Golf ball 100 may have a total diameter of at least 42.67 mm. Golf ball 100 may have a total weight of about 45.4 g. Golf ball 100 may have a total compression deformation of about 2.65 mm.

In another exemplary embodiment, first layer 204 may have a first thickness or diameter between about 24.4 mm and about 24.6 mm, and in some embodiments may have a thickness of about 24.55 mm. First layer 204 may have a first weight between about 8.15 g and about 8.45 g and in some embodiments may have a first weight of about 8.30 g. First layer 204 may have a first hardness between about 49 Shore D and about 53 Shore D, and may in some embodiments have a first hardness of about 51 Shore D. In some embodiments, first layer 204 may be made of a blend of materials including one or more highly neutralized acid copolymers. Fourth layer 206 may have a fourth thickness between about 6.85 and about 7.15 mm, and may in some embodiments have a fourth thickness of about 7 mm. Fourth layer 206 may have a fourth weight between about 24.25 g and about 25.15 g and in some embodiments may have a fourth weight of about 24.7 g. Fourth layer 206 may have a fourth hardness between about 55 Shore D and about 60 Shore D, and may in some embodiments have a fourth hardness of about 60 Shore D. In some embodiments, fourth layer 206 may be made from a compound including butadiene rubber. In some embodiments, core 212 may have a core compression deformation between about 3.6 mm and about 4.1 mm, and in some embodiments may have a compression deformation of about 3.85 mm. In some embodiments, an intermediate layer may be inserted between first layer 204 and fourth layer 206. In some embodiments, the intermediate layer may be made of a film made at least partially of ethylene vinyl acetate. The intermediate layer may have an intermediate layer thickness between about 0.01 mm and about 0.05 mm, and may in some embodiments have an intermediate layer thickness of about 0.03 mm. The intermediate layer may have an intermediate layer weight between about 0.1 g. Second layer 208 may have a second thickness between about 0.80 mm and about 1.1 mm, and may in some embodiments have a second thickness of about 0.95 mm. Second layer 208 may have a second weight between about 5.0 g and about 6.2 g, and may in some embodiments have a second weight of about 5.6 g. Second layer 208 may have a second hardness between about 65 Shore D and about 69 Shore D. Second layer 208 may be made partially or completely from a polyurethane resin. Third layer 210 may have a third thickness between about 1 mm and about 1.2 mm, and may in some embodiments have a third thickness of about 1.1 mm. Third layer 210 may have a third weight between about 6 g and about 7.4 g, and in some embodiments may have a third weight of about 6.7 g. Third layer 210 may have a third hardness between about 53 Shore D and about 57 Shore D, and may in some embodiments may have a third hardness of about 55 Shore D. Third layer 210 may be made partially or completely from a polyurethane resin. Golf ball 100 made with these layers may have a ball diameter between about 42.67 mm and about 42.9 mm, and may in some embodiments have a ball diameter of about 42.7 mm. Golf ball 100 may have a ball weight between about 45 g and about 45.8 g and may in some embodiments have a ball weight of about 45.4 g. Golf ball 100 may have a ball compression deformation between about 2.25 mm and about 2.75 mm, and may in some embodiments have a ball compression deformation of about 2.5 mm. Golf ball 100 may have a ball COR between about 0.778 and about 0.795, and may in some embodiments have a COR of about 0.783.

A golf ball made according to the embodiments described herein, with the various layers having the hardness, flexural modulus, COR, and compression characteristics described above, is believed to have improved feel and play characteristics. When hit with a driver, the COR of the core tends to control the performance, and a golfer may experience a long, accurate drive. When hit with a short iron or wedge, the hardness of the cover tends to control feel and performance, and a golfer may experience improved feel and increased spinnability due to the relatively soft outer cover and relatively hard inner cover.

While various embodiments of the invention have been described, the description is intended to be exemplary, rather than limiting and it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible that are within the scope of the invention. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents. Also, various modifications and changes may be made within the scope of the attached claims. 

What is claimed is:
 1. A golf ball, comprising: a first core layer having a first flexural modulus; a mantle layer disposed radially outward of the first core layer, the mantle layer having a second flexural modulus; and a cover layer disposed radially outward of the mantle layer, the cover layer having a third flexural modulus, wherein the second flexural modulus is at least twice the first flexural modulus; the second flexural modulus is at least fifty times the third flexural modulus; and the first flexural modulus is at least six times the third flexural modulus.
 2. The golf ball according to claim 1, wherein the second flexural modulus is between two and eight times the first flexural modulus.
 3. The golf ball according to claim 2, wherein the second flexural modulus is between fifty and one hundred eighty times the third flexural modulus.
 4. The golf ball according to claim 3, wherein the first flexural modulus is between six times and thirty times the third flexural modulus.
 5. The golf ball according to claim 1, wherein the second flexural modulus is between fifty and one hundred eighty times the third flexural modulus.
 6. The golf ball according to claim 5, wherein the first flexural modulus is between six times and thirty times the third flexural modulus.
 7. The golf ball according to claim 1, wherein the first flexural modulus is between six times and thirty times the third flexural modulus.
 8. The golf ball according to claim 1, further comprising a second core layer between the first core layer and the first cover layer.
 9. The golf ball according to claim 1, wherein the first flexural modulus is between about 6000 PSI and about 40000 PSI, the second flexural modulus is between about 50000 PSI and about 100000 PSI, and the third flexural modulus is between about 200 PSI and about 3000 PSI.
 10. The golf ball according to claim 9, wherein the first flexural modulus is between about 7000 PSI and about 30000 PSI.
 11. The golf ball according to claim 9, wherein the second flexural modulus is between about 50000 PSI and about 90000 PSI.
 12. The golf ball according to claim 9, wherein the third flexural modulus is between about 300 PSI and about 2000 PSI.
 13. A layered article, comprising: a first layer having a first flexural modulus; a second layer having a second flexural modulus; and a third layer having a third flexural modulus; wherein the second layer and the third layer are positioned adjacent one another; the first flexural modulus is between six times and thirty times the third flexural modulus; the second flexural modulus is between fifty and one hundred eighty times the third flexural modulus; and the second flexural modulus is between two and eight times the first flexural modulus
 14. The layered article according to claim 13, wherein the second layer is positioned between the first layer and the third layer.
 15. The layered article according to claim 14, further comprising a fourth layer, wherein the fourth layer is positioned between the first layer and the second layer.
 16. The layered article according to claim 15, wherein the first layer is a first thermoplastic material, the second layer is a second thermoplastic material, the third layer is a third thermoplastic material, and the fourth layer is a thermoset material.
 17. The layered article according to claim 16, wherein the first thermoplastic material comprises at least one of an ionomer resin, a highly neutralized acid polymer composition, a polyamide resin, a polyester resin, a polyurethane resin, and a combination thereof; the second thermoplastic material comprises at least one of an ionomer resin, a highly neutralized acid polymer composition, a polyamide resin, a polyester resin, a polyurethane resin, and a combination thereof; and the third thermoplastic material comprises at least one of an ionomer resin, a highly neutralized acid polymer composition, a polyamide resin, a polyester resin, a polyurethane resin, and a combination thereof.
 18. The layered article according to claim 17, wherein the second thermoplastic material is the same type of material as the third thermoplastic material.
 19. The layered article according to claim 16, wherein the thermoset material comprises a rubber compound synthesized using a rare earth element catalyst.
 20. The layered article according to claim 15, wherein the first layer has a first specific gravity, the second layer has a second specific gravity, the third layer has a third specific gravity, and the fourth layer has a fourth specific gravity; and wherein the fourth specific gravity is at least 0.01 greater than the first specific gravity, the second specific gravity is at least 0.01 greater than the fourth specific gravity, and the third specific gravity is at least 0.01 greater than the second specific gravity. 